Are Pregnant Moms More Likely to Use Pot Than Their Peers?

A new study published in the Annals of Internal Medicine reveals some pretty surprising stats about marijuana use during pregnancy. The one that's grabbing headlines everywhere? Pregnant teens are more than twice as likely to use pot than other girls their age.

More specifically, 14 percent of expecting teens (ages 12 to 17) indicated they used marijuana in the past month versus 6 percent of non-pregnant teens.

How this compares to other age groups:

- 4 percent of all pregnant women reported marijuana use during pregnancy.

- Out of those ages 18 to 25, 6 percent of pregnant women used marijuana versus 14 percent of non-pregnant women.

- Marijuana use was much lower for adults 26 and older, at less than 2 percent of pregnant women versus 5 percent of non-pregnant women.

How use breaks down by trimester:

- Almost 6.5 percent of all pregnant women reported marijuana use during the first trimester.

- More than 3 percent reported use during the second trimester

- And almost 2 percent reported use during the third trimester.

Other demographic breakdowns:

- Non-Hispanic blacks were more likely than other groups to use pot during pregnancy. (Non-Hispanic black: 6.5 percent; Non-Hispanic white: almost 4 percent; Hispanic: Almost 3 percent; Non-Hispanic other: more than 1 percent).

- Family income inversely correlated to pot use during pregnancy. More than 6.5 percent of pregnant women with a family income less than $20,000 a year used marijuana versus almost 2 percent of those with a family income greater than $75,000 a year.

The recent findings come from a 2002 to 2015 National Survey on Drug Use and Health that included 410,000 females ages 12 to 44. About 14,400 of the participants were pregnant during the poll. Because these surveys are self-reported, marijuana use is most likely underestimated across all demographics, though the evidence strongly points to it being higher among teens. But why?

“Though we cannot establish causality, it is very likely that teens who are more prone to risk-taking generally may be more likely to both use marijuana and to have unprotected sex," said Dr. Nora Volkow, the study's lead author and director of the National Institute on Drug Abuse in Maryland.

According to Volkow, young people are also increasingly viewing marijuana not just as benign but as beneficial.

More and more pregnant women are using marijuana to ease nausea, relieve stress and anxiety and manage pregnancy-related pains, arguing that there's limited evidence on marijuana's effects on the developing fetus.

Dr. Judy Chang, an associate professor of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh say these risks include, “scrawnier babies, kids who have some problems with their thinking and learning abilities (and) kids who find it harder to do more complicated brain tasks when they are teenagers."

Chang, who is not involved with the survey, also tells CBS News that studies show, "even when pregnant patients say that they are using pot to treat morning sickness, the use actually started before they got pregnant."